re. Optimal rpm for fuel economy???

[Swann, Benjamin R. (BSWANN)]

>>Rob Beatty wrote:

>>Let the arguing commence :)

>Mihnea Cotet wrote:

Well, I'd say that it is pretty weird as fuel consumption depends on fuel 
mixture and RPM, (the gear you're in). HP also depends on RPM and on torque 
and I think that the most economic RPM is the one that burns fuel the most 
efficiently.> yadayadda.>

It is interesting that these older cars seem to get as good of mileage as
todays cars, and better than the EPA estimates.

I typically get 25 MPG combined driving - not conservative driving.  If I
was concervative It'd be far higher..say in the 30's especially on the
highway.  Optimal cruising speed & RPM for the 5KCSTQW is right around 60
MPH or 2800 RPM in 5th gear, where on a flat stretch(maintaining course and
speed), the car will get 37 MPG.  Most of the reason the overall economy is
lower is most of the fuel is used accelerating to the optimal speed, and the
faster the acceleration, the more wasteful.

I'm sure the turbo helps with fuel conservation, as it is more than just in
theory re-capturing waste heat.  Also, the 5K has a lower CD than most
earlier cars, and that helps.  On the highway the 5k gets better gas mileage
than the 4k which has a higher cd.  Around town, they more or less even out,
because the 4k is a much lighter car.

Of course I only touched on a few of the factors here.  Compression ratio,
displacement, fuel, coefficient of leadfootedness, etc. there are many more
variables to factor in.

my $.02

Ben